<?php


$fp =fopen("/dev/ttyACM0", "w+");
if( !$fp) {
        die("error");
}
 fwrite($fp, "9");
 $var = fread($fp, 1);
 while(strlen($var)==0){
  $var = fread($fp, 1);
 }
 echo trim($var);
// fclose($fp);
?> 